Abstract

Large volumes of liquid waste are generated in processing operations of seafood industry. Such effluents have high concentrations of soluble protein, but it is necessary to concentrate it for utilization. Therefore, the present study investigated the effects of the use of hydrochloric (HCl) and trichloroacetic (TCA) acids on biochemical and antioxidant properties of recovered solids from sardine stickwater (SSW) and tuna cooking water (TCW). After centrifugation of both raw effluents, solids recovery was performed with the pH-shift method separately using 5 N HCl and 40% TCA as precipitating agents. Specifically, protein recovery was effective (> 80%) only for SSW when both acids were used. An increasing of high-molecular-weight peptides (17 to 158 kDa) in recovered solids resulted from a protein aggregation boosted by the precipitating agents. Concentration of some essential amino acids (Lys, Leu, Ile, Phe and Val) were increased in recovered solids. Except to recovered solids of TCW at pH 11, a low protein solubility (20 to 13%) was observed after treatment with both acids. Elimination of low-molecular-weight peptides and some antioxidant AAs result in a loss of free-radical-scavenging activity, but an increase in ferric reducing antioxidant power was registered for protein concentrates of TCW.

Graphic abstract

中文翻译：

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pH值变化从渔业废水中回收的固体的生物化学和抗氧化特性（沙丁鱼粘水和金枪鱼自来水）

摘要

海鲜产业的加工过程中会产生大量的液体废物。这样的流出物具有高浓度的可溶性蛋白，但是有必要对其进行浓缩以进行利用。因此，本研究调查了盐酸（HCl）和三氯乙酸（TCA）的使用对从沙丁鱼粘水（SSW）和金枪鱼自来水（TCW）中回收的固体的生化和抗氧化特性的影响。将两种原料废水离心分离后，分别使用5 N HCl和40％TCA作为沉淀剂，通过pH转换法分别进行固体回收。具体而言，当同时使用两种酸时，蛋白质回收仅对SSW有效（> 80％）。回收的固体中高分子量肽（17至158 kDa）的增加是由于沉淀剂促进了蛋白质聚集。回收的固体中某些必需氨基酸（Lys，Leu，Ile，Phe和Val）的浓度增加。除了在pH 11下回收的TCW固体外，在用两种酸处理后均观察到较低的蛋白质溶解度（20％至13％）。消除低分子量肽和一些抗氧化剂AAs会导致自由基清除活性的损失，但是TCW蛋白质浓缩物中铁的还原性抗氧化能力有所提高。

图形摘要